ST. LOUIS -- In the two days since he was injured in a nasty collision at home plate, Yadier Molina has made a "miraculous" recovery, and he could be back on the field by the end of this week.

Molina was released from a St. Louis-area hospital on Monday and was back at the ballpark on Tuesday. He was diagnosed with a concussion -- his second in two seasons -- but no other injuries as a result of his collision with Phillies infielder Eric Bruntlett.

"The pain in my neck went away," said Molina. "The neck feels fine. My body feels fine. It's just the headaches. I'm going out, going to stretch with the team, try to run out on the field. If I feel fine, a couple of days and I'll be back."

That may be a bit optimistic, given that Molina is still experiencing symptoms of his concussion. But the worry was that the situation would be much worse.

"It's miraculous," general manager John Mozeliak said. "We're living right, right now. We're very fortunate for that news."

The Cardinals chose not to make a roster move, indicating their confidence that Molina's absence would be brief. Jason LaRue started at catcher on Tuesday night and will handle the catching duties in Molina's absence. Aaron Miles is the most likely candidate to catch in an emergency, but Molina might be available if desperately needed.

"He said he feels better," manager Tony La Russa said. "We could use him in an emergency, but we'll definitely try not to use him. He wants to play tomorrow but I don't know. Whenever he's cleared."